Learn about the imaginary unit, "i", a unique number defined as the square root of -1. It's a key part of complex numbers, which are in the form a + bi. The powers of "i" cycle through a set of values.

Explore the introduction to imaginary numbers, their properties, and applications through interactive lessons and examples on Khan Academy.

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Learn about the imaginary unit i, about the imaginary numbers, and about square roots of negative numbers.

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Sal explains how we obtain complex numbers by adding real numbers and imaginary numbers.

Introduction to imaginary numbers, their properties, and how they are used in algebra.

a is called the real part of the number, and b is called the imaginary part of the number. The table below shows examples of complex numbers, with the real and imaginary parts identified. Some people find …

But in my brain, when I think of a complex number, I think of it having a real number and an imaginary number. And if someone were to say, well, what part of that is the imaginary number?

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